1. Technical Field
The present invention relates to a color designation control device, a color designation control method, and a color designation control program.
2. Related Art
In the image processing field, in some cases where a scanner reads a color image, by allowing a user to designate a desired color, a highlighting process or a drop-out process may be performed on the designated color. Such methods of designating a color are mainly classified into the following two methods. The first method is a method of displaying a hue (hue circle) represented as a circular graph, a linear spectrum, or a color palette in a user interface (UI) screen on a display of a personal computer (PC) and designating a desired color of a user from the hue circle, the spectrum, or the color palette. As a related art, there is a known parameter setting method of setting a range (an upper limit and a lower limit) of each color parameter by displaying axial images, which correspond to color parameters such as lightness data BRT and hue scales ROP, GOP, and POP, on the screen and by allowing an operator to perform a cursor operation (refer to JP-A-9-145633).
The second method is a method of allowing a user to optionally designate a point within a preview image displayed on a UI screen and designating the color corresponding to the designated point. As a related art, there is a known color designating/extracting device that designates a color by allowing an operator to designate one point with a mouse or a light pen in a color image displayed on a display and extracts a color in a predetermined range based on the designated color (refer to JP-A-5-128225). Further, there is a known drop-out color processing device that displays a pseudo 3-dimensional histogram as a result of conversion of an input RGB image based on HSV (hue, saturation, value (lightness)), clicks a certain point in the histogram image, extracts a color set (a branch) relating to the clicked color, and designates the branch as a drop-out color range (refer to JP-A-2009-159185).
In the first method, the surrounding environment (such as illumination) at that time also has an effect on the user. For this reason, it is difficult to accurately designate a color, which is identical to the color to be originally designated in the color image, from the hue circle, the spectrum, or the color palette, in a way of visually confirming the color. That is, it is difficult for the user to perform an intuitive operation. Accordingly, in order to finally obtain a desired effect (the highlighting or the drop-out of the desired color), it is necessary to repeat the operation or improve an operating skill.
In the second method, a point within the preview image is selected, and thus there may be a range in the color, which is a designation target desired by the user, in the preview image (there may be unevenness in the color which is a desired designation target). In this case, the entire target is not necessarily highlighted or is not necessarily made to drop out, and there is a concern that unevenness occurs in the result of the highlighting or drop-out process. Further, as disclosed in JP-A-5-128225 and JP-A-2009-159185, even in the case where the predetermined color range including the designated color is extracted, the color range extracted in such methods may not be the color range the user really wants. Hence, in some cases, it may be difficult to obtain the result of the highlighting process or the drop-out process that obtains user satisfaction.